i get this weird sounds like a fluttering sound. only when i accelerate. i have no idea what it is just started happening. its coming from the engine duh, but you can hear it from in side the car but no noise when out of gear and i accelerate only when in gear and i accelerate. its a kinda like a pining noise maybe a piston spring ??? Please help
Well first off, there is no such thing as a piston ring. What are you refering to?
Check your oil first. See if its low or really black. If you’re low enough on oil, it will make noise while accellerating. Check that first, then get back to us cause there are many more things it could be.
-Steve
Does the sound seem to come from near or under the battery? If so…it’s probably the ABS system. I don’t know how that would be related so closely to the acceleration of the car, though.
Do you have an automatic or manual transmission?
Originally posted by DAY U IZ
Well first off, there is no such thing as a piston ring.
actually there is. 
It could be an exhaust leak…
^^ think he ment spring. But anyways check to see if one of the bolts broke between your cat and your headers. sometimes the engine torque will snap the spring bolt that hold them together and it will make your car sound like sh!t.
Weird sound when Acceerate really bad!!
I think ill check the Oil that sound like it might help, also the broken bolts might be it cause i just got a Weapon R header and installed a cat back system. I did mean the Piston Spring. and i have a Manual. also i dont have ABS but i sounds like its coming from under the car. Thanks for all your help keep it coming though.